Broken US Robotics 5637 USB modem

  • Thread starter Thread starter Man-wai Chang ToDie (33.6k)
  • Start date Start date
I got rid of it many years ago, no idea. As I said several posts up,
if you cut a lead you can try all combinations to see if one works.
Such odd modems are unlikely to be common, but they do exist. They
must have sold with a nonstandard lead when new.







and the 4th wire is a spare. Nonetheless it wouldnt work (outgoing) on
any combination of 2 wires, only 3.

NT
Click to expand...

As I was drifiting off to sleep I think figured out what was going on.
By passing the ac signal to the ringer line it avoids the need for one
capacitor on the modem board. It still needs to use the other not-
ground phone line wire to switch between on and off hook, as thats dc
signalling. One capacitor is saved, and the custom leads cost no more
than a standard one. A few cents per modem adds up over a large number
sold. But the downsides are that it wont work on 2 wire extensions,
and wont work with a standard lead. The inevitable slew of customer
returns wouild explain why it was an unusual approach.


NT
 
Franc said:
No, the voltage comes from the batteries at your local telephone
exchange (or CO as the Americans call it).

- Franc Zabkar
Click to expand...

Then I need a special tool to measure the jack....

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and Farce be with you!
/( _ )\ (Xubuntu 8.04.1) Linux 2.6.27.2
^ ^ 20:14:01 up 9:33 0 users load average: 2.44 2.41 2.35
¤£­É¶U! ¤£¶BÄF! ¤£´©¥æ! ¤£¥´¥æ! ¤£¥´§T! ¤£¦Û±þ! ½Ð¦Ò¼{ºî´© (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa
 
No, the voltage comes from the batteries at your local telephone
You seem lost.
Click to expand...

It should not be that complicated to determine whether my modem is
broken.... All I need to do is to send it back to US and have my cousin
to test it on US's phone jacks.

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and Farce be with you!
/( _ )\ (Xubuntu 8.04.1) Linux 2.6.27.2
^ ^ 11:13:01 up 1 day 32 min 0 users load average: 1.09 1.06 1.00
¤£­É¶U! ¤£¶BÄF! ¤£´©¥æ! ¤£¥´¥æ! ¤£¥´§T! ¤£¦Û±þ! ½Ð¦Ò¼{ºî´© (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa
 
david said:
I wouldn't call a voltmeter a special tool.
Click to expand...

He is talking about gaining access to the bare wire.

The trick would be finding an RJ-11 with nice wire ends
(spade lugs) on the other end. Then, one of those
wall jacks with screw terminations, would expose the
connections, and allow you to connect the modem.

Wall_outlet --- RJ-11 ----cable----- Screw_down_wall_jack ---- Modem_plugs_here

This is an example to illustrate the spade lugs on the
end of an extension cord. This one has an RJ-45 and not
an RJ-11.

http://www.l-com.com/productfamily.aspx?id=707

http://www.l-com.com/item.aspx?id=7937

Using that concept, you can make a phone extension
cable, and use the screw heads for the meter measurement.
Since the extension cable unplugs, that makes it
easier to wire up the cable. (Not like working
at the demarc with live wiring...) Tape up and
insulate any unused wires.

HTH,
Paul
 
He is talking about gaining access to the bare wire.

The trick would be finding an RJ-11 with nice wire ends
(spade lugs) on the other end. Then, one of those
wall jacks with screw terminations, would expose the
connections, and allow you to connect the modem.

Wall_outlet --- RJ-11 ----cable----- Screw_down_wall_jack ---- Modem_plugs_here
Click to expand...

If you have an internal modem, then you could use the exposed pins at
the rear of the PCB as test points.

- Franc Zabkar
 
Wall_outlet --- RJ-11 ----cable----- Screw_down_wall_jack ----
Modem_plugs_here

This is an example to illustrate the spade lugs on the
end of an extension cord. This one has an RJ-45 and not
an RJ-11.
http://www.l-com.com/productfamily.aspx?id=707
http://www.l-com.com/item.aspx?id=7937
Click to expand...

Thanks. Your reply is kept.

I still think the modem is broken and had sent it back to my cousin in
US using expensive courier service. :)

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and Farce be with you!
/( _ )\ (Xubuntu 8.04.1) Linux 2.6.27.3
^ ^ 12:22:01 up 2:17 3 users load average: 1.01 1.02 1.03
¤£­É¶U! ¤£¶BÄF! ¤£´©¥æ! ¤£¥´¥æ! ¤£¥´§T! ¤£¦Û±þ! ½Ð¦Ò¼{ºî´© (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa
 
one slip and byebye modem
Click to expand...

AFAIK, the adjacent pins are not connected, or are behind a bridge
rectifer, so I would think that damage is unlikely. The telephone line
is designed to tolerate a short circuit, so touching the probes
together would not be a problem, either. I'd be careful of any ringing
voltage, though. I don't know what 90VAC feels like, current limited
as it may be, but I wouldn't like to find out.

Anyway, I have a couple if dead, or expendable, internal modems that I
can use for this purpose.

- Franc Zabkar
 
Back
Top